1. Field of the Invention
The present invention relates to an operating board for controlling the operation of industrial robots and other automatic machines, or more particularly, to a hand-held portable teaching apparatus suitable for operating these machines or teaching jobs to them.
2. Description of the Related Art
In teaching a series of operations to an industrial teaching playback robot (hereinafter merely called "the robot"), the robot is actually operated manually, and various data thus generated are edited and stored or necessary data is added in accordance with the operations and stored as required. This teaching process is often implemented in the neighborhood of the robot, that is, within the operating range of the robot by a handheld manually-operable teaching apparatus. As a result, the operator is exposed to the danger of an erroneous operation or runaway of the robot.
Some means is required to secure the safety of the operator (teacher). A teaching apparatus equipped with such means is capable of producing a signal only when a key for designating the direction of operation or the conditions for operation of the robot, for example, is depressed directly. Should the operator lose his consciousness, however, and fall on the teaching apparatus, the keys would remain depressed. In the case of an error in robot operation or a runaway thereof, on the other hand, the operator might be upset and unable to perform proper stopping operations.
In order to solve this problem what is called a "deadman switch" may be provided, which ignores the entries of keys in view of the fact that the hand of the operator leaves the teaching apparatus, in most cases of emergency such as the loss of consciousness. Patents related to this type of apparatus include JP-A-60-153789 (UM), for example.
Conventional teaching apparatuses suggested include a deadman switch operated by the thumb. In these prior art apparatuses, keys are operated in most cases by the forefinger of the idle hand not holding the apparatus, and when it is desired to operate a pair of keys at a time, the operator may want to use also a finger of the hand holding the teaching apparatus. The thumb which is the only idle finger of the hand holding the teaching apparatus, however, is already occupied to operate the deadman switch. As a consequence, the simultaneous operation of a pair of keys by both hands has not been realized. Also, the thumb is easily exhausted as the operation of the deadman switch is concentrated on the thumb.